Process of purifying burner-gases.



No. 822,373 PATBNTED JUNE 5, 1906. R. KNIETSCH. PROCESS OF PURIFYING BURNER GA$ES.

APPLIGATION FILED AUG. 5,1898.

m? s J Mflzesses: i I lm'enlor W w; MMZ

7 5y Jig/a UNITED STATES PATENT OFFICE.

(crummy, A courounxox OF NEW. roux.

BY \IESNE ASSKil'h'l ENTS. TO GENERAL CHE M CAL PROCESS OF PURIFYlNG BURNER-GASES- ivo. 822,373.

- Specification of Lettarslctaht.

Patented June 5, 1906 mimiccarn l-minis. s mnmeamrc.

many, have invent-ml n cvrtuin now and useful lrcccsh c2 lurifviug Bumcqllascs, cf which tlic following is :l. spcrificzitiuuf I V v In my Lcttcrs Patent Nos 552119; 686,023, and 6232.013 I have described imnrcvcmcuts in the manulncturc of sulfuric anhydrid and a new uppura'tus for uc there in, having for its chjcct the )racticnlly (111531 titnlivc ccuvcrsinn of the sulfur iliuxid in sulitii'uus ucid gases into sulfuric anhydricl iiy the contact process by mcaus of the reign latcd cooling of time contents of the cuutact-. chamber, so as tu mniutaiu'tlic tcmpcrgturc thereof substantially between the composing and tlcuompusing temperature of sulfuric Rnllylilld lu-uig'fcrmcd I have cliscccc-rcd that 1 can achieve saul result mantxuucuslrand invariably while supplying unpurc su fur-dicxil l gases to the cunt-act material prcr' 4 Yltlflil the impuritics in such gases do not in-" elude ccrlain substances t-lic delctcriuui; influence of which was first rl'mcovered by me. By the a pplicntiun of this ciiscuvcryl can produce in said pruccss. frmu bur'uerscs (by which I mean such impure 'sul ur-dioxid gases as are prcduccd or are similar to those producel {rum burning pyritcs, crude sulfur, or utlwr sulfur containing raw materials) a Dractlcalh' continuous approximately quantiLat-ivv yield cl sulfuric anhydrid with sulficint ccoilmny fur general cmnmcrcial application. The principal mnstitucnts cf ordinurv pyritcs are the fullcwing elements or cumpuumls tlwrcnf: ircn, uluugunsc, copper, nickel, arsenic, anlimuny; ilmsplmrus, men cur lcurl, zinc, hisnmth; tluillium, selenium, iQr. Many of tlu-sc nu l'flillfitillg tllc orc-S arr liable in pa; intu tlulxulmrf-guSOS, either [rec or in cumliinutiun, i'itllvr as dust or as gas llvcn il' practically purc sulfur he used as the mun-c cl S( some sulfuric uuhyrlrirl is fcrnuwl, :uul Sill"? thourc usml in burning contains moisture llw rrsult is'tlzutthe SO, prmlunml rmitnins sull'uric unhyilrid which phrases Ecrwanl as a suspvmled mist.

llitlwrtc it. has lmcu supposed that the dcttiiuruil'm in ullicivnr) of the cuntact materznl was due to lis ws, lust, and soot, and the rum l of those has been unsuccessfully atte mptci hy llrucchriuical purification; but I havc disccveted that besides these the imguriticc in said burncrgases,.which inter- .re with the continuousaccomplishmcnt cf scid-rcsult b tlic contact prccess cf my clmve-refcrrc -tc. patents, are substantially the sullurrll, arseuicul, and mercurialimpuntics," of, i in other words, sulfuric acid mist, .aullurvapcr, arsenic, mam; ,smi thc comimmune the last two '1 mac substances wcrcuuglcrstccdta be volatile at a red heat, wliiclijis the: approximate temperature at which sulfuric unhydrid was known to be ccmpcscdfrom sulfur dicxid and oxygen, -aml.v I believe that no one until myself, suspcctcil that they cxercisc l any dctcricratiug nfiuncccn the contact material.

My 1mm departsfrom the apparently evident wa'yrof inuuediately palssin intc the ccntcct mass the relatively dry and lot roasting-gasc after having freed them frcm dust -as rm cc possible}: It isubstitutcs a new and particular purification which preferably c0nsistsin the following features: first,- a special tre atmcnt of the gases while but with a jet of steamprpther agitator; second, a subsequent. gradual cooling; third, retrieval of condensed Impurities; fourth, successive washings with water or sulfuric acid until sufficiently pure,

as may be dctermiucil by especial tcstm' fifth, said tcts consisting, lmstmf an cptical' test to sllcw frceclcm from dust and mist, and secondly, of a chemical analytical test to show freedom from arsenic, mercury, and their compoundsjsixtli, drying the grapes by sulfuric acid. To achicv'c this purity, a jet of steam is blown into the hot gases as they crnaiialte from the Y itcs burner. 'Plus steam prcrluccs the in owing efi'ectsi,

' First. It mixes the gases th'rouglily and brings about a more perfect ccmbuticn of anyfsullur "or other combustible matter. This mixture and rcmotcd cmubustlcn can alsc lic cllcctcd wit l a. jet of air or other combustion-promoting gas-My a portion of the urificri gases re'udy for the contact rcccss; lint then the steam must he lilcwu in ater.

V Secund. I havc fcund that it is prcfcralalc far the purpose of an easy and tctal waslrmg of the roastingaces, especially from pyrltcs containing muc arsenic, tp cool the gases riot suddenly, but gradually, in suitcble cooling apparatus. Since, howcver, all 881d gases contain concentrated sulfuric-acid vapors which are condensed when themetals f the cooling apparatus, usua 1y consistin of' with sulfuric acid uickly deposit on the in-.

nor walls of the coo are or conduits asva. hard -'crust, which stops up the pi es and, like boiler incrustations, 1s diflic t to remove. By blowing steam into the hot uses this formation of crusts is avoided an the said imin series, and pumping mac 'mer "especially 0 purities form a mud which is easily collected. and removed.

Fourth. Further, the addition of the manlrendersit possible to more easily wash the gases subsequently and gives greater cer tainty ofattaining the desired purity.

Fifth. Finally, the action of the steam serves to avoid the formation'of-volatile hydrogen compounds of the admixed impm'ities,

arsenic or its compounds, which also could be formed b the action of the concentrated sulfuric aci on the metals of the coolers and the impurities and which can be removed only with great difficulty, therefore passing into the contact mass and slowly rendering it inactive.

The gases after having been treated b steam pass on through an iron or brick wor flue, in which they cool gradually, into a system of lead pipes arranged to act as a cooler. Here they are cooled down to about 100 ce'ntigrade or less. At this point the mud containing the impurities is conveniently re-'- moved from the path of further incoming gases. They are then passed into washingtowers or other washing apparatus and washed with water or dilute or concentrated sulfuric acid. If not alread washed with concentrated sulfuric acid, t ey finallv are thoroughly dried with this concentrated acid or other drying agent. The extent'to which the washing must be carried out must be determined by the aid of the tests already mentioned and will depend on the nature and de gree of impurit to be eliminated. This washingis best e ected in asystem of washing bottles or other washing a paratus set up is used to move the gases relatively to t e washing liquid. The washing li uid will at the beginuin of the operation a sorb some sulfurous aci as, butwill soon become saturated, so thatt esulhirous-acid aswillfrom-thattlme on simpl pass throng .the washin liquid without further absorbed there y. If

If, however, a quantity of'stepm' ssasva it requires considerable ex enditure of power to remove it from the was ng a paratus and because the said apparatus is liable to become 'incrusted. The washing apparatus can be constructed on the principleof the ordinary washing-bottles,.sot at thegase have to overcome the pressure of the. liquids. in them, and consequentl the liquid which is in constant movement comes intimately mixed with the gases, pr the gases may be scrubbed by the energetic movement 6f. the washing liquids through the gases. No material should be used in the washin apparatus which in the resence of the aciddiquid might give rise to t e production of noxious gasesfor instance,-arseniureted hydrogen. Sulfuric acid and any sublimates and flue-dust are precipitated in-the cooler and any going over are held in the washing apparatus, and the liquid ruumn from these is collected in lead boxes and al owed togsettle. The sulfuric acid obtained in this way can be oured off from the sediment and be .used as lluted sulfuric acid or it can be converted into concentrated sulfuric acid by the sulfuric anhydrid obtained bv' the contact process. If not already washed with concentrated sulfuric acid, the gases are finally thoroughly dried by means of such concentrated acid or other ent.

The extent to which the washing must be carried will depend upon the nature and amount of the impurities to be eliminated and can be determined b tests, asaforesaid. These tests are more full described as follows: In'the first place t e apparatus is so arranged that a layer of the gas some yards lon is illuminated by means of a lamp at one en while from the other end the operator can look through the entire layer of gas toward the li ht. It is necessary that no dust or mist mixture shall be observable. f this isemonstrated by the optical test, it is only necessary to examine the gases for such impurities as would not be shown by the optical test. Among these impurities there is ih articular arsemureted hydrogen and possib y also mercury vapors. norder todetect these, a portion of the stream of the purified gas is'passed for a long periodsay twentyour hours-thronghawash-bottle containing distilled water,-and the water so treated is then examined according to any-suitable chemical analytical method.- Inthis way any considerable traces of the dangerous 1mpurities can be discovered.

The above description of the process a plies most closely to the rification of e gases derived from the maces in which pyrites are burned orroasted; but gissscontaining sulfur dioxid fromother sources can be urified in a similar way. in rectical wor in it is easy and best to eil'cct oth the ohove-Lcscribed tests in the nnlnucr LlL" scribed; but of course if the chemical tcstalone constantly indicated the freedom of thc gases from all traccscf noxious impuriti'cs the optical tcst could be dispensed with. 7

In the accompanying drawings I have shown an apparatus by which my process may be successfully erfornied. Figure 1 thereof is a vertical niegramniatic section, and Figs. 2 and 3 are modifications of ccrlriiu parts. In Fig. I the 'pyrites-hurncr pus, for c.\- ample, leaves the pyritcs-hurncr K by way of the dome A, at whose exit the gas mccts u jct of steam B, above referred to,,end posses a long and through thc'pipe B, in which the gas isv raldually cooled, and thence into the cooler where it is further cbolcd'hy means of, say, a. cooling liquid circulated through tower D around the gas-passages ou'. from the liquid-inlet o enin c to the liquidmutlet openings 6'. 'is ac amber orpocliet for the reception and removal of im critics dc posited in the cooling-tower. )n leaving tower D the gas next passes 'threugh the above-referred-to washing apparatus Fl E and thence into the drying-tower F, which is filled with coke J, which is sprinkled with concentrated sulfuric acid supplicd through the sprinkler G. T he dried gas lrzivcsthej tower F by the passage H. L

. Fig. '2 represents another form of washing apparatus which me be used in place of F,

of Fig. 1. The water enters thi fuppcr compertment through the pipe iund gsrnpcs from the lower compartment through the fpipc i. 'lhc gas enters through the pipe I and escapes through thc pi 1c 1'. The comertnients are formed in t w lo'ocr h the horizontal partitions m, m, m, and "m", rcspectively, containing the npwurdly-cxuuulmg nipples n, n, n, and n, covcrcd by the hoods n o o 0, so as to hriru; thc upwardlymoving gases in intimate. contact with tho downwardly-moving watcr in the passages between said hoods and nipples.

Fig. 3 re resents unotlu'r form of dryingtower in which the coke is arranged in hori zontal layers 9' j 7" j, which are sprinkled with concentrated sulfuric acid entcringthe apparatus through the pin rality of sprinklers g g g. The gas to he dried cntcrs this drier at I: and leaves it at h I claim V V i. in the manufacture of sulfuric anhydrid by the contact proccss, the proocss of purifying burnergases which consists in agitating such gases while hot, and thou cooling and washing the gases, and drying them. 7

2. In the manufacture of sulfuric anhy I drid hy the contact proccss, ihc pruccss of unifying hurrwr guscs which consists in lvlowing: a jot of steam into said gnscs u'hilc they ztl'e ho! to agitate tlzcru and rcduvc thcir mu culration, nndthen cooling. washing and drying said gascs.

3. In the manufacture of sulfuric anhydrid h the contact pruccss, the process hcrcin dcscrihcd of prcpnriru, hurncr-gascs for purification, which proccss consists in first commin ling thorn with uqucnus va ior so as to Ft! unc thc concentration uf'cmu lcnsed ncid conniincd (heroin and then gradually doling said guscs. and lhcrcupnn removing inipuritics m dcscrihcd I. in the manufacture of sulfuric anhydrid h the cuntuct proccxs, the. process oi treating hurncr-ginscs which consists in rd, moving substantially all urscnical impurity therefrom prior to conversion.

5. in the manufacture of sulfuric anhydrid by tlwcontact proccss, the process of- !reatiru: luu'ncr-gnscs which consuls in rc-' moving suhshmiiully all arseniral and morcurial impurity therefrom prior in conversron. l

o. Inlthu nmuufacturn of sulfuric nnhy drid by the contact pruccss, the process of ircritiili; hurncwgascs which consists in rcrnoviug suluumtudlr all sulfur and arscnic-ul inipurily therefrom hcfurc convcl'sion.

7. In tho manufucturc of sulfuric unliv' drid by lhc contact pruccss. the process hf trcntiug lmrncr-grrcs which consists in remm ing suhsiantiully all sulfur, sulfuric Mid and arscnicnl impurity llwrci'roni prior to convcrsion- S. in lhc numnlucturc of sulfuric null drid h tho contact process, the process of purifying burner-gases which consisis in agitating; tho gnscs in tho' ircscucc of moisture and gradually cooling liicnn and washing the gases in a liquid suturmmlwith sulfurou acid gas. 9. In tho manufacture of sulfuric anhvdrid h lhc contact proccss, the process hf purifying hurrwr-gnsr-s which consists in agitating tho gnscs and gradually cooling thorn, and washing tluun in a liquid suturutcdwith sulfurousucid gun.

lll.- ln thc nuuiufucturc of sulfuric nnhvdrill hy the contact process, the process hf protcctiug the contact substance which con sisls in separating out of the. burner-gases, the nrscniciil impurity, substantially as and, by thc uicnns (inscribed.

I In the manufacture of sulfuric anhw drid h the contact process, the process of purifying. burnerases which consists in cooling them gradually and continuously removing solid ini unties, than brin ng them in contact wit a. liquid capable 0 rernoving liquid and gaseous impurities, 'and finally drymg themr In testimony whereof I hiwe hereunto set 12. In -the menufacture of sulfuric anhymy hand in the presence of two snbscribing drid by the contact process, the process of treating burner-gases which consists in first wltnesses.

cooling them gradually, then continuously RUDOLPH KNIETSCH; 5 removing a part ofjhe impurities, and then VVitnesses:

passing the gases through a liquid capable GUSTAV L. LICHTENBERGER,

of removing the remaining impurities. ADOLPH REUTLINGER. 

